Mozilla
Senior Software Engineer, WebExtensions
Remote Firefox role with clear candidate location fit.
PostedRecently added
Eligible countries2 accepted countries
Seniority signalSenior
Work settingRemote
Accepted candidate locations
CanadaFrance
Role overview
Senior Software Engineer, WebExtensions
Requirements and responsibilities
Readable role content extracted into sections for faster review.
Details
- Implement and maintain WebExtensions APIs and Addon Management, balancing power, safety, and performance, as well as user interfaces in Firefox.
- Debug and fix issues affecting extensions in Firefox.
- Collaborate with product managers, QA, and the AMO engineering team to deliver features end-to-end.
- Contribute to Mozilla-owned extensions and system add-ons.
- Participate in open source workflows: code reviews, pull requests, and discussions in Bugzilla/GitHub.
- Support extension developers by helping diagnose issues and improving tooling/documentation.
- 4+ years of professional experience in software development.
- Strong proficiency in JavaScript, DOM APIs, HTML, and CSS.
- Familiarity with modern browser architecture and debugging tools.
- Experience with API design and integration.
- Ability to navigate and learn from large codebases.
- Strong communication skills and experience collaborating in distributed teams.
- Bonus points for:
- Experience with Firefox internals, C++ or Rust.
- Familiarity with Android or GeckoView development.
- Knowledge of web security principles.
- Contributions to open source projects, especially in browser or extension development.
- Experience with Firefox internals, C++ or Rust.
- Familiarity with Android or GeckoView development.
- Knowledge of web security principles.
- Contributions to open source projects, especially in browser or extension development.
- Generous performance-based bonus plans to all eligible employees - we share in our success as one team
- Rich medical, dental, and vision coverage
- Generous retirement contributions with 100% immediate vesting (regardless of whether you contribute)
- Quarterly all-company wellness days where everyone takes a pause together
- Country specific holidays plus a day off for your birthday
- One-time home office stipend
- Annual professional development budget
- Quarterly well-being stipend
- Considerable paid parental leave
- Employee referral bonus program
- Other benefits (life/AD&D, disability, EAP, etc. - varies by country)
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